I chose to go with the Hankook Ice Bears 440, mainly after monitoring the Canadian site for quite some time and learning that a lot of people were complaining about both the life span and the 'grip' of the Continental winter tires (even though they are rated approximately the same on tire distributors websites). I ordered mine from Fast Eddy in Canada when he was running a winter tire special and I was buying them months before my car arrived and nobody else seemed to know 'squat' about Smart cars at that time.
I also decided to go with steel rims, small (moonie hubcaps from Smart) and the air pressure sensors, so my alert would not be lit up all winter long. I thought about just using the sensors from my stock wheels but then I figured eventually I would have more money invested in breaking them down two times a year and would run a much higher risk of damaging them in the switch overs. It was a good amount of money initially, but now that it's done, I'm SO GLAD I did it RIGHT! Now, I can swap the wheels myself without having to involved others and I have an operable Tire Pressure Monitoring System all year around.